RFID reader and RFID system
Provided are an RF reader and an RF system. The RF reader includes: a plurality of antennas; a path selector for selecting a transmit or receive path of an RF signal; an RF processor for processing the RF signal received through the transmit or receive path of the path selector; and a controller for controlling the path selector selecting a path.
1. A radio frequency identification reader comprising:
a phase lock loop section generating an input radio frequency signal;
a signal distributor receiving the input radio frequency signal from the phase lock loop and outputting a first radio frequency signal and a second radio frequency signal;
a phase shifter receiving the first and second radio frequency signals from the signal distributor, creating a phase differential between a first phase of the first radio frequency signal and a second phase of the second radio frequency signal, and modulating the first and second radio frequency signals according to data received as input to the phase shifter;
a signal selector for selecting one of the first and second radio frequency signals from the phase shifter as transmitting signal according to a modulation type; and
a controller for controlling a signal output path and period of the phase shifter and signal selector.
2. The radio frequency identification reader according to claim 1 , wherein the controller operates selectively based on one of DSB-ASK, SSB-ASK and PR-ASK modulation types.
3. The radio frequency identification reader according to claim 1 , wherein the phase shifter adjusts the first and second radio frequency signals to create a 180 degree phase differential between the first and second phases of the two radio frequency signals.
4. The radio frequency identification system comprising:
one or more of passive electronic tags; and
a radio frequency identification reader having a plurality of antennas and communicating with the one or more passive electronic tags by different modulation types according to coding formats;
wherein the radio frequency identification, reader comprises:
a phase lock loop section generating an input radio frequency signal;
a signal distributor receiving the input radio frequency signal from the phase lock loop and outputting a first radio frequency signal and a second radio frequency signal;
a phase shifter receiving the first and second radio frequency signals from the signal distributor, creating a phase differential between a first phase of the first radio frequency signal and a second phase of the second radio frequency signal and modulating the first and second radio frequency signals according to data received as input to the phase shifter;
a signal selector for selecting one of the first and second radio frequency signal from the phase shifter as a transmitting signal according to a modulation type; and
a controller for controlling a signal output path and period of the phase shifter and signal selector.
5. The radio frequency identification system according to claim 4 , wherein the radio frequency identification reader comprises a first switch connected on each of the antennas by a switching of the plurality of antennas, a second switch connected to the first switch for selecting the transmit or receive path of the radio frequency signal, and a third switch connecting a signal inputted through the second switch to a ground or the receive path according to a transmit or receive mode.
6. The radio frequency identification system according to claim 4 , wherein the radio frequency identification reader comprises a radio frequency transmitter for outputting a radio frequency signal modulated selectively by one of DSB-ASK, SSB-ASK and PR-ASK modulation types.